The present invention relates to an ink jet recording method, a recording device and a data processing method in which high quality images can be formed on a recording material with suppressed banding nonuniformly, more particularly to the ink jet recording method, the recording device and the data processing method in which the recording is carried out through one-path or multi-path printing.
The present invention is applicable to any equipment using as the recording material, paper, textile, leather, nonwoven fabric, OHP sheet, metal or the like. More particularly, the present invention is applicable to a printer, copying machine, facsimile machine or another office equipment, industrial manufacturing machines or the like.
As regards the recording on the recording material using the recording apparatus, the demand for high-speed printing picks up. In order to increase the printing speed, it is one of the methods to refuse the number of paths in the multi-path printing which has been proposed to accomplish formations of high quality images. Here, the number of paths is the number of scans of the carriage required to complete one line of printing.
Since the number of ejection outlets of the recording head is limited, the amount of the sheet feed for units can is smaller if the number of paths is larger. On the other hand, the sheet feeding distance per unit can can be increased by reducing the number of paths. For example, in the case that printing is carried out in the two-path mode, the speed can simply be doubled by changing it to one-path printing. That is, the reduction of the number of paths reduces the number of scans to cover a predetermined area (one sheet, for example), and increases the distance of sheet feed, so that time required for printing is shortened.
In the case that recording ahead having a plurality of ejection outlets for ejecting the recording liquid (ink) scans the recording material in the direction perpendicular to the direction in which ejection outlets are arranged, an image is formed in an image area in the form of a band by one scan of the recording head, as shown in FIG. 21.
Thus, in the case of the one-path printing, the duty (ratio) of the recording ink ejected per unit time is larger than when the one band area is printed through a plurality of scans (multi-path printing). Therefore, the production of the black stripe between the adjacent bands (paths) is remarkable at the portions where the printing duty is high, although it is different depending on the nature of the recording material and the recording liquid.
The problem is more significant in the case of lateral arrangement of the recording heads in which cyan, magenta and yellow recording heads or the like are arranged in the main scan direction. This is because the boundaries appear at the same position. FIG. 6 schematically shows the laterally arranged recording heads.
The black stripe appearing at the adjacent bands is called connecting stripe, spending or the like. It might deteriorate the image to such an extent that image is practically unsatisfactory.
Therefore, a method of avoiding the banding in one-path printing is disclosed, thus improving the image quality.
For example, Japanese Laid-open Patent Application 11-188898 discloses a serial scanning type in which a recording head repeatedly scans the recording material in the main scan direction to print the image band by band, a method is used to avoid the production of a stripe at the connecting portion between the adjacent bands. More particularly, at least one of the first and the last raster lines of one band covered by one scan of the recording head is divided into a plurality of unit areas including a predetermined number of dots. In accordance with the image data, more particularly, with a sum of an amount of ink ejection for a noting color in each of the divided areas and an amount of ink ejections for the other in the unit areas, the amount of the ink actually ejected is reduced (thinning).
However, in the conventional method, the accuracy of the suppression of the banding in the case of plain paper or the like with which the banding tends to occur.
Accordingly, it is a principal object of the present invention to provide an ink jet recording apparatus, a recording method and a data processing method with which the banding is suppressed even in the case of one-path printing.
According to an aspect of the present invention there is provided an ink jet recording apparatus for effecting recording on a recording material by ejecting ink with relative scanning movement between a recording head and the recording material, said ink jet recording apparatus, comprising:
obtaining means for obtaining information indicative of an amount of ink to be ejected to each of unit areas provided by dividing an area in the neighborhood of a boundary between adjacent bands of scanning recording of said recording head on the recording material; and
control means for controlling an amount of being to be ejected to the unit area on the basis of the output of said obtaining means,
wherein the unit areas exist astride the boundary between adjacent one of the bands.
According to another aspect of the present invention there is provided an ink jet recording apparatus for effecting recording on a recording material by ejecting ink using a recording head having a plurality of recording elements, said ink jet recording apparatus comprising:
recording scanning means for effecting recording with relative scanning movement between the recording head and the recording material in a main scan direction;
subscanning means for imparting relative scanning movement between the recording material and the recording head in a direction which is different from the main scan direction substantially each time after completion of recording scan in the main scan direction;
dot count means for counting ink ejection data number for each of unit areas provided by dividing an area in the neighborhood of a boundary between adjacent bands of scanning recording of said recording head on the recording material;
determining means for determining a thinning rate for each of the unit areas on the basis of an output of said dot count means, and
thinning means for effecting a thinning process to the ink ejection data on the basis of the thinning rate determined by determining means,
wherein the unit areas exist astride the boundary between adjacent one of the bands.
According to a further aspect of the present invention there is provided an ink jet recording apparatus for effecting recording on a recording material with relative scanning movement between a recording head and the recording material, said ink jet recording apparatus comprising;
obtaining means for obtaining information indicative of an amount of ink to be ejected to each of unit areas provided by dividing an area in the neighborhood of a boundary between adjacent bands of scanning recording of said recording head on the recording material; and
control means for controlling an amount of the ink ejected to an area to be thinned in the unit area on the basis of an output of said obtaining means;
wherein the inks of the unit area and the area to be thinned are different from each other.
According to a further aspect of the present invention there is provided an ink jet recording apparatus for effecting recording by ejecting ink onto a recording material on the basis of data using a recording head for ejecting the ink through a plurality of nozzles, said in jet recording apparatus comprising:
recording control means for imparting relative movement between said recording head and the recording material and rejecting thing from said recording head in accordance with ink ejection image data to sequentially effecting recording operations for adjacent recording areas by the ink ejected from the recording head; and
correcting means for counting data indicative of ejection of the ink for boundary areas of adjacent recording areas and reducing the ejection data for the boundary areas.
According to a further aspect of the present invention there is provided a method of correcting image data for an ink jet recording apparatus for effecting recording by ejecting ink onto a recording material on the basis of data using a recording head for ejecting the ink through a plurality of nozzles, said apparatus imparting relative movement between said recording head and the recording material and rejecting thing from said recording head in accordance with ink ejection image data to sequentially effecting recording operations for adjacent recording areas by the ink ejected from the recording head, the improvement residing in:
a step of correcting the ink ejection data by counting data indicative of ejection of the ink for boundary areas of adjacent recording areas and reducing the ejection data for the boundary areas.
According to the present invention, the unit areas as a whole are astride the adjacent bands, the behavior of the ink in the boundary therebetween can be properly analyzed.
By using different sizes for the dot count area and the thinning area, appropriate thinning is possible.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
FIG. 1 is a partly broken perspective view of an ink jet recording apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic perspective view of a major part of a recording head used in the apparatus of FIG. 1.
FIG. 3 is a block diagram of a control circuit for an ink jet printing apparatus according to an embodiment of the present invention.
FIG. 4 is a flow chart of process steps according to a first embodiment of the present invention.
FIGS. 5A and 5B illustrate an area for which a dot counting operation of the print data is carried out and an area in which the thinning is executed.
FIG. 6 is a schematic view illustrating a structure of the recording head according to the first embodiment of the present invention.
FIG. 7 is a flow chart of color area discrimination steps according to the first embodiment of the present invention.
FIG. 8 is a schematic illustration of an example of a dot count in a unit area according to the first embodiment of the present invention.
FIG. 9 shows an example of the sections of the color areas according to the first embodiment of the present invention.
FIGS. 10A and 10B show an example of a thinning rank graph according to the first embodiment of the present invention.
FIG. 11 shows an example of the count in a SMS process according to the first embodiment of the present invention.
FIGS. 12A to F show an example of a thinning rank graph according to the first embodiment of the present invention.
FIGS. 13A and B illustrate a mechanism of ink bleeding occurring at the connection between adjacent bands.
FIGS. 14A-D illustrate a print data processing using the SMS process according to the first embodiment of the present invention.
FIGS. 15A-F illustrate a print data processing using the SMS process according to the first embodiment of the present invention.
FIGS. 16A-C schematically illustrate a recording head according to a second embodiment of the present invention.
FIG. 17 shows an example of the sections of the color areas according to the second embodiment of the present invention.
FIGS. 18A and B illustrate an example of a dividing method in a color area according to the second embodiment of the present invention.
FIGS. 19A to F show an example of a thinning rank graph according to the second embodiment of the present invention.
FIGS. 20A to F show an example of a thinning rank graph according to the second embodiment of the present invention.
FIG. 21 is a schematic view illustrating a band and boundary.
FIGS. 22A-E illustrate a thinning process using a mask according to an embodiment of the present invention.
FIGS. 23A and 23B are schematic illustrations of behavior of the recording ink on the recording material.
FIG. 24 is a flow chart of thinning process at the boundary between the adjacent bands according to the second embodiment of the present invention.
FIG. 25 is a schematic illustration of a Table to be used in the thinning process.
FIG. 26 is an illustration of a thinning process for the image data in a buffer.